rDNA片断序列分析技术及其在植物系统与进化研究中的应用

The Analysis Techniques of Ribosome DNA and Application of rDNA in Phylogenetic and Evolutionary Studies of Botany

根据PCR RFLP分析、微卫星序列分析、SSCP分析和核酸序列分析的原理及技术要点及其在rDNA序列分析中的具体运用, 以及nrDNA在植物分类学、植物系统发育、中药材道地性鉴定及 5SrDNA在鉴定体细胞杂种方面的研究进展, 确认核rDNA是一个优良的分子标记, 主要体现在: 序列能够提供足够多的具有系统发育信息的核苷酸位点, 且该序列易于排序, 在植物分类、系统发育等方面应用前景广阔.

The sequence of rDNA has become an important nuclear locus for molecular systematic investigations of botany in recent years, and the technique of rDNA spacer sequence get great development. One of the internal transcribed unit of nuclear rDNA is composed of 18SrDNA, ITS1, 5.8SrDNA, ITS2 and 26SrDNA. ITS1 and ITS2 can be readily amplified by PCR and sequenced using universal primers. Nuclear rRNA genes in botany are arranged in long tandem repeating usits, much like those of other higher eukaryotes. Owing to rapid concerted evolution, the repeat units have homogenized or nearly so in most species. The sequences contain many variable sites and potential informative sites among related species, and have been proven to be a useful molecular marker in phylogenetic and evolution of botany. 5SrDNA are also arranged in long tandem repeating units, which was widely used in identification of somatic hybrid. The paper has generally reviewed the principle and keystone of PCR-RFLP, SSR, SSCP and nucleic acid analysis. In the paper, we also report the application of nrDNA in botany taxonomy, botany phylogeny, identification of genuine crude drugs and identification of somatic hybrid using 5.8SrDNA. Nucleolus ribosome DNA can be used in not only systematics and evolution of botany but also phylogenetics et al.